Art of producing molded pulp articles



March 1, 1932. M. P. c |APL|N ART 'OF PRODUCING MOLDED PULP ARTICLES Filed Oct. 4, 1928 In ventar Mrlellflbaplin Patented Mar. 1, 1932 UNITED STATES, PATENT OFFICE MERLE P. CHAPLIN, OF WATERVILLE, MAINE, ASSIGNOR, BY MESNE ASSIGNMENTS, TO FIDELITY TRUST COMPANY, OF PORTLAND, MAINE, A CORPORATION OF MAINE,

AS TRUSTEE ART OF PRODUCING MOLDED PULP ARTICLES Application filed October 4, 1928, Serial No. 310,391.

According to one phase of my present in-' vention I propose to spray the pulp solution under pressure onto the face of the die itself as the die travels past the sprayer. This re- ,sults in a more uniform distribution of the pulp fibres on the die as well as avoiding the necessity for the die travelling through a part of its movement in a vat containing the pulp solution. Moreover by spraying the pulp solution onto the die under pressure I am enabled to dispense with the necessity for any separate pressing and shaping die, as the impact of the sprayed pulp solution is sufficient properly to densify and compact the fibres, although such a pressing die may of course be additionally used if further compacting action is desirable.

According to another phase of my; present invention, I propose to dry the article either wholly or in part on the forming .or collecting die itself, thus dispensing with the usual drying tunnel if I dry to substantially complete dryness on the forming or collecting die, or where drying to a lesser degree than substantial complete dryness on the forming or collecting .die itself, utilizing such drying tunnel for the final drying but substantially reducing the length of the drying tunnel as compared with present installations.

In either case the forming or collecting die will be of relatively considerably larger diameter than the dies now commonly employed with as great a travel time as is practicable or necessary whereby materially to increase the length of drying time that the article remains on the die.

The actual drying itself may be accomplished in any of a variety of ways. The die may be surface heated as by electricity, hot air, steam, or other medium, or the die with deposited article thereon may be caused to travel through a dryin chamber which is supplied with any suitable drying medium, as steam or hot air whereby the article on the die will be dried to the desired degree of dryness during such passage through such drying chamber.

4 In connection with such arrangement, however, it is important to note that where hot dry air, for example, is used as the drying medium the effect of the vacuum is to draw the hot air through the formed articles themselves, thus not only resulting in a quicker drying action but drying to a substantially greater degree of dryness than is possible by mere surface heat in the same amount of time and incidentally avoiding the danger of baking or charring the articles themselves.

he timeof drying travel of the die and the degree of drying heat may be varied according to the amount of moisture which it is desired to extract from the article and according to such other factors as may be present, as for example, the kind of pulp being ing or collecting dies is employed and where-' in the arrangement is such that a vacuum is created through the forming or collecting dies for the major part of their orbit which vacuum is automatically discontinued and compressed air sent through the dies for the remaining portion of their orbit. Such a machine has become practically standard in the art and is therefore disclosed herein as indicating the ready adaptation of the principles of my present invention to present equipment without substantial modification or reorganization of such equipment. It will be understood,'of course, that such treatment is purely illustrative and in no way limiting and that my invention may be used with other types of pulp molding machines. In fact, as an obvious reversal, I may deposit the pulp on the forming and collecting die by vacuum rather than by spray impact, and my invention is therefore applicable to such machines as operate upon this principle of pulp deposition.

In the drawings Fig. 1 is an end elevation, partly in section,

of a pulp molding machine equipped for the practice of my invention.

Fig. 2 is a fragmentary detail showing a modification, and

Fig. 3 is a similar view showing a further modification.

I have indicated at 1 a movable die carrier which for the purpose of this application may be considered as a rotary carrier adapted to be revolved continuously m the direction of the arrow A from any suitable driving source about the horizontal axis 2 and provided with one or more radial series of hollow die carrying arms 3 terminating at the periphery of the carrier in forming or collecting dies 4 perforated as at 5 and of the proper size and shape to form the ultimate article from the pulp deposited thereon during the rotation of the carrier relative to the pulp supply source.

As is customary in a machine of this type mechanism is provided whereby vacuum is applied to the collecting dies through an initial phase of their revolution as indicated by the arrow B, .together with automatic means for shutting off the Vacuum and sending a blast of compressed air through the dies during a subsequent phase of their revolution. Such mechanism is old and well known in the art and forms no part of my invention.

Where the pulp supply source is a vat or tank T (Fig. 2) containing the pulp solution,

the individual dies 4 successively pass through the vat itself during a portion of their revo- 1utionand during such period the vacuum created through the dies draws onto the dies themselves a suflicient quantity of the pulp solution to form the ultimate article.

Although useful in such capacity I have disclosed in this application an arrangement (Fig. 1) whereby the pulp may be deposited on the individual dies under pressure. For this purpose I mount adjacent tothe path of movement of the dies a nozzle 6 which rotates in properly timed relation to the rotation of the die carrier. Such nozzle is provided with a plurality of spaced jet ports 7 adapted successively to register with a relatively stationary port 8 in a pulp solution supply pipe 9 mounted within the nozzle itself and communicating with any suitable supply of solution under pressure.

By this arrangementthe pulp solution is sprayed with sufiicient force onto the face of each die 4 as it passes the rotary nozzle to result in a proper densification or compacting of the fibres on the die, the vacuum being on at such time to assist the compacting action and to take care of the water of the solution.

In order to take care of any excess solution which is not taken up by the die itself the rotary nozzle is arranged within a vat or tank 10 which may be provided with any suitable return connection to the source of pulp solution supply whereby the excess solution is returned to the supply source for reuse.

Arranged within the tank on one or both sides of the jet nozzle are spaced partitions 11 and 12 which act as deflectors or baffles to prevent deposition of the solution on the dies adjacent to the die opposite the nozzle which is being exposed to the spray nozzle.

If desired I may arrange adjacent to the spray nozzle itself a cleaning jet nozzle 13 by means of which a stream of water, steam or other cleaning fluid may be directed intermittently or continuously against the spray nozzle whereby to keep it free of accumulations of fibre thereon which might tend to clog said nozzle. Similarly I may arrange in advance of the fibre depositing nozzle 6 another cleaning nozzle 14 the purpose of which is to clean the forming dies of any accumulations of fibres remaining thereon prior to exposure to the spray jet of the pulp depositing nozzle 6. This last named cleaning nozzle may be baffled as indicated at 15 and 16 the baffle 15 extending as a partition across the bottom of the tank for the purpose of preventing the water or other cleaning fluid from commingling with the pulp solution contained in the tank proper.

By this construction I am enabled to spray under pressure the pulp solution directly on the face of each collecting and forming die as it passes the rotary nozzle. The size of the ports is so related to the surface area of the dies that a predetermined or metered charge of pulp solution may be directed 'at each die thus making for uniformity of the ultimate product.

As each die passes out of the spray jet the deposited fibres are held thereon by the vacuum. It has usually been considered necessary at this stage to apply pressure thereto in order to form and shape the article and this has ordinarily been done by a die carrier employing a plurality of presser dies corresponding in number to the number of forming and collecting dies and which presser dies upon release of' the vacuum received the articles from the forming and collecting dies.

Under my method of pulp deposition such presser dies are unnecessary, however, the forming and collecting die carrier instead being of considerably larger diameter than has heretofore been the case so as to prolong the drying travel of the articles thereon, and the articles being dried on the forming and collecting dies themselves rather than by transfer to a separate drying tunnel. For

this purpose the collecting and forming dies may be heated in any suitable manner as by electricity, steam, hot air, or'the like, and as here shown are heated by passage through a drying cha1nber.- Such drying chamber is indicated at 17 and is defined by an enclosure 18 disposed about the path of rotation of the die carrier for any desired distance so that the dies in their rotation enter and arecarried through and out of the drying chamber. The drying agent, as for example, hot air or steam is admitted into the drying chamber through any suitable inlet 17', and during the passage of the dies through the chamber the vacuum is still on as indicated by the arrow B so that throughout all of the time that the dies are within the drying chamber the drying medium, as hot air, is being drawn by the vacuum through the articles on the dies thus resulting in a quicker and more complete drying action than is possible where the dies are merely surface heated and the vacuum is not employed to draw the heat through the article.

In order further to assist such penetrative drying action, the drying medium, as hot air, may be admitted into the drying chamber under pressure. Such an arrangement is shown in the modification of Fig. 3, wherein I have indicated at 21 an inlet into the drying chamber for hot air under pressure, or other fluid drying medium. Where hot compressed air or like fluid is used as the drying medium, however, it is advisable to battle the articles on the dies against direct exposure thereto, and accordingly I arrange within the drying chamber between the dies and the hot air inlet 21 a perforated bafile 22. The drying medium passes through the perforations 23 of such baflie and in conjunction with the suction through the dies themselves results in a very complete drying of the articles on the dies as they are carried through the drying chamber, or the hot air blast itself may be depended upon alone to retain the articles or the dies.

After passage through the drying chamber the formed and substantially dry articles are ejected from the forming and collecting dies during the compressed air phase of travel ofthe dies. The ejected articles may drop by gravity into a delivery belt 19 by means of which they are conveyed to the point where they are to be counted, stacked, and packaged. If further drying is desirable to extract such moisture as may not have been extracted in the drying chamber itself, the conveyor belt may be caused to travel throu h a drying tunnel as indicated at 20.

I t us form and dry the article on the forming or collecting die without the necessity of using presser dies as heretofore in the art, and in the embodiment shown, I utilize the vacuum phase of the apparatus 5 for the purpose of drawing the drying heat through the article. Where drying on the forming and collecting die is not desired,

however, I may employ the usual presser and transfer dies of the prior art and dry subsequently, as in the usual drying tunnel.

Such an arrangement might be especially desirable where the pulp is deposited on the dies under pressure, as by the spray jet of Fig. 1. Where such spray jet is employed, it will be noted that the cleaning jet from the nozzle 13 successively flushes out the ports 7 of the spray nozzle 6 as said nozzle rotates therepast, thus preventing clogging.

The position of the article on the die may be reversed from that shown, that is to say the article could be made with its bottom surface towards the die in which event the inside surface of the article could be smoother or calendered by any suitable smoothing or calendering device without removal of the article from the forming-die.

Various other modifications in method and apparatus may all be resorted to within the spirit and scope of my invention as defined by the appended claims.

What I thereforeclaim and desire to secure by Letters Patent is:

1. The method of die molding pulp articles which consists in arranging in co-operative relation to each other a spray jet connecting with a source of pulp supply under pressure and a movable forming and collecting die, and in discharging. liquid pulp under pressure through said spray jet onto said die as said die moves therepast.

2. The method of forming molded pulp articles which consists in arranging in cooperative relation to each other a spray jet connectingwithasource of pulp supply under pressure and a movable forming and collecting die, in discharging pulp under pressure through said spray jet onto said die as said die moves therepast, and in applying heat to dry the article on said die,

3. The method of die molding pulp articles which consists in. providing a valved spray member communicating with a source of pulp solution under pressure, in moving a forming and collecting die past said spray member, and in operating the valve of said spray member in timed relation to the movement of said die to deposit a charge of pulp on said die as it moves therepast. 4. The method of die molding pulp articles which consists in providing a valved spray member communicating with a source of pulp solution under pressure, in moving a die carrier having a plurality of forming and collecting dies past said spray member, and in operating the valve of said spray member in timed relation to the movement of said dies to deposit successive charges of pulp on said dies as each die moves into a position substantially opposite thereto.

5. In a pulp molding machine, a spray member communicating with a source of pulp solution under pressure, a forming and collecting die movable into and out of the effective influence of said spray member, and a valve controlling the discharge of the pulp solution from said spray member and operating in time relation to the movement of said die.

6. In a pulp molding machine, a relatively stationary spray member communicating With a source of pulp solution under pressure, a forming and collecting die rotatable into and out of the effective influence of said spray member, and a rotary valve controlling the discharge of the pulp solution from said spray member and operating in timed relation to the movement of said die.

7. In a pulp molding machine, a spray member communicating with a source of pulp solution under pressure, a forming and collecting die movable into and out of the effective influence of said spray member, a valve controlling the discharge of the pulp solution from said spray member and operating in timed relation to the movement of said die, and means for applying heat to dry the article on the die.

8. In a pulp molding machine, a movable die carrier presenting a plurality of forming and collecting dies, a relatively stationary spray member communicating with a source of pulp solution under pressure and disposed to project a pulp jet against the face of each die as it is moved past said spray member, and a valve controlling the discharge of the pulp solution from said spray member and operating in timed relation to the movement of said die carrier. 9. In a pulp molding machine, a rotating die carrier presenting a plurality of forming and collecting dies, a relatively stationary spray member communicating with a source of pulp solution under pressure and disposed to project a pulp jet against the face of each die as it is rotated past said spray member, and a rotary valve controlling the discharge of the pulp solution from said spray member and operating in timed relation to the rotation of said die carrier.

10. In a pulp molding machine, a rotating carrier presenting a plurality of forming and collecting dies, a relatively stationary spray member communicating with a source of pulp solution under pressure and disposed to project a pulp jet against the face of each die as it is rotated past said spray member, a valve controlling the discharge of the pulp solution from said spray member and operating in timed relation to the rotation of said die carrier, and means defining a drying chamber disposed about a part of the orbit of the die carrier through which the dies are successively rotated after deposition of the pulp solution thereon by the spray member whereby to dry the articles on said dies.

11. The method of die molding pulp articles which consists in intermittently discharging a liquid pulp solution under pressure on to successive rotating dies and in subj ecting the articles so formed to a continuous drying during another phase of their rotation.

12. In pulp molding apparatus, a' rotary series of forming dies, means for intermittently discharging pulp on said dies successively and means for continuously drying said articles so formed on said dies during another portion of their orbit.

13. In pulp molding apparatus, a rotary series of forming dies, means for creating suction on said dies during a portion of their orbit, means for intermittently discharging pulp on said dies successively While under suction.

14:. In pulp molding apparatus, a rotary series of forming dies, means for creating suction on said dies during a portion of their orbit, means for intermittently discharging pulp on said dies successively while under' suction, and means for continuously drying the articles on the dies during another phase of their orbit.

15. The method of die molding pulp arti''- cles which consists in moving a forming die past a pulp deposition source, and in discharging liquid pulp under pressure from said pulp deposition source onto said die as said die moves therepast, and in thereafter applying heat to said die to dry the formed article thereon.

16. The method of die molding pulp articles which consists in moving a forming die past a pulp deposition source, and in discharging liquid pulp under pressure from said pulp deposition source onto said die as said die moves therepast and in timed relation to the movement of said die.

17 The method of die molding pulp articles which consists in moving a forming die past a pulp deposition source, and in discharging liquid pulp under pressure from said pulp deposition source onto said die as said die moves therepast and in timed relation to the movement of said die, and in thereafter applying heat to said die to dry the article thereon.

In testimony whereof I aflix my signature. J Y MERLE P. CHAPLIN. 

